Intermediate work

Modify parser to support {::pipe ...} and {::pipe.coactive ...}
Add method clauseTokens to Clauser but the result is not what I expected...
I have an array of 1 (TOKEN_EOC) and 2 (TOKEN_OTHER), not an array of strings (tokens).
This is because the current implementation needs just to skip correctly the tokens (TOKEN_OTHER),
and to recognize the end-of-clause (TOKEN_EOC).
After thoughts, I think it's time to expose the parser classes and to make them available from
a user script (to do on a specific branch).